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Re: Translation versus tunneling document
On 2007-12-11 09:36, Iljitsch van Beijnum wrote:
On 8 dec 2007, at 20:34, Brian E Carpenter wrote:
Would it be possible to evaluate deployment issues, i.e., whether
said mechanism is already available today in hosts, and if it isn't,
whether it can easily be implemented in a modular way so it can be
added by others than the OS vendor?
I think you also have to consider whether there's something to
tunnel *to* - is there a significantly large class of dual stack
services that will be able to make use of tunnels? And don't forget
the third class of solution: application level proxies. Would
you advise the operator of a large IPv4-only web site to
a) dual-stack the whole site
b) install a dual-stack proxy for IPv6 clients
c) install a layer 3 translator for IPv6 clients?
As I said in the second session, dual stack isn't an appropriate
mechanism for client computers. If we had that kind of address space we
wouldn't have to have this discussion.
I agree. That's why my question was about a server site.
Proxies are good but generally don't address UDP applications
My question was specifically about a web site.
and are
ususally a binary thing: either you proxy pretty much everything or you
don't proxy at all. However, a mechanism where only sessions towards
destinations using the unsupported IP version are proxied would be very
useful, and if everyone who isn't dual stack used one, referrals
wouldn't have to be a problem, either.
A layer 3 translator is basically a more generic implementation of a
proxy.
Well, no; it specifically lacks understanding of the application layer.
It has the advantage that it can support more protocols than most
proxies and possibly v4-v6-v4 operation, which would be nice in a
situation where you have IPv4-only legacy devices but an IPv6-only network.
Again I'm confused - are you talking about clients or servers? Why would
anyone be operating IPv4-only servers on an IPv6-only network? (They
may be operating IPv4-only applications, but that's where you might
consider BIS or even DSTM.)
Brian